Ok, ok. It's not really Rainbow Road. It's a glitch found by AmetDj2. But if you close your eyes real tight and replay the fond memories of performing the famous shortcut on Mario Kart's rainbowy space track, you...won't see a damn thing in your game of Forza Horizon and probably crash into something. What'd you expect when you closed your eyes? Sheesh, who told you to do that?